输入: [1,3,5,6], 5
输出: 2

输入: [1,3,5,6], 2
输出: 1

输入: [1,3,5,6], 7
输出: 4

输入: [1,3,5,6], 0
输出: 0

class Solution {
    public int searchInsert(int[] nums, int target) {
        int low = 0, high = nums.length -1;
        if(target < nums[low])
                return low;
        else if(target > nums[high])
                return high + 1;
        while (low <= high){
            int middle = (low + high ) >>> 1;
            if(nums[middle] > target)
                high = middle - 1;
            else if(nums[middle] < target)
                low = middle + 1;
            else 
                return middle;   
        }
        return low ;
    }
}